style(frontend): 接入 stash-ui 设计系统

- 依赖 @stash/ui（file:../../stash-ui），统一引入 style.css 与 Toaster
- 任务面板、表单、弹窗、日志、状态标签全部迁到组件库，App.css 只保留页面布局
- 移除自写 useFocusTrap，改用基于原生 dialog 的 Modal
- 修复 LogViewer 流式追加时误判离开底部、导致不再自动跟随的问题
- 发布脚本检查 stash-ui 产物；README 补充组件库构建与 file: 依赖刷新说明

frontend/e2e/dashboard.spec.ts

@@ -77,7 +77,7 @@ test('manages a task and reads a real run log', async ({ page, request }) => {
   // Cron 预览是异步渲染的，等它稳定后再点击，避免点击坐标在弹窗重排中失效。
   await expect(newTaskDialog.locator('.cron-run-item').first()).toBeVisible()
   await newTaskDialog.getByRole('button', { name: '选择文件夹…' }).click()
-  const directoryPicker = page.getByRole('dialog', { name: '选择项目工作目录' })
+  const directoryPicker = page.getByRole('dialog', { name: '选择工作目录' })
   await expect(directoryPicker).toBeVisible()
   const directoryPathInput = directoryPicker.getByLabel('目录路径')
   await directoryPathInput.fill(workingDir)
@@ -140,7 +140,7 @@ test('manages a task and reads a real run log', async ({ page, request }) => {
     path: 'test-results/dashboard-log-drawer.png',
     fullPage: true,
   })
-  await drawer.getByRole('button', { name: '关闭运行日志' }).click()
+  await drawer.getByRole('button', { name: '关闭' }).click()
 
   await page.getByRole('button', { name: '编辑' }).click()
   const editor = page.getByRole('dialog', {
@@ -161,10 +161,10 @@ test('manages a task and reads a real run log', async ({ page, request }) => {
 
   await page.getByRole('button', { name: '删除' }).click()
   await page
-    .getByRole('alertdialog')
+    .getByRole('dialog', { name: /删除任务/ })
     .getByRole('button', { name: '确认删除' })
     .click()
-  await expect(page.getByRole('heading', { name: '还没有任务' })).toBeVisible()
+  await expect(page.getByText('还没有任务')).toBeVisible()
 })
 
 test('keeps the dashboard usable on a narrow viewport', async ({